Hawaii’s unemployment rate rose to 6.4 percent in September, the highest rate in nearly a year, the state reported today.

The increase in the jobless rate occurred despite the economy adding 6,300 payroll jobs, including an estimated 800 new positions at Disney’s Aulani Resort at Ko Olina.

The September unemployment rate rose from 6.2 percent in August, and matched the previous high of 6.4 percent in November 2010. The unemployment rate is adjusted for seasonal variations.

Officials at the state Department of Labor and Industrial Relations said the “divergence” between the unemployment rate and the payroll job count was probably due in part to an increase in the number of people working more than one job.

For example, someone who took a second job at Aulani would count only once in the labor force employment data used to calculate the unemployment rate. However, that person would count twice in a separate survey of employers used to calculate payroll jobs, the officials said.

While the two sets of data sometimes diverge on a month-to-month basis they follow a similar trend over the longer term, the officials said.

Hawaii County has the highest unemployment rate in the state at 9.5 percent, down from 9.6 percent in August. Kauai County’s rate rose to 8.7 percent in September from 8.6 percent the month before. The rate rose to 7.9 percent from 7.5 percent in Maui County. In Honolulu County the rate rose to 5.7 percent from 5.5 percent. The county data are not seasonally adjusted.